So my school has a ton of these scattered around… are these of any rarity?
I will make a separate post with the fire alarm system in my school
Depends on the age I think. We have one remaining in a tiny room at my school. It’s the last remnant of an old masterclock system we had that died in 2020.
Here’s some older clocks for you. These came out of an old school I salvaged some bells from in December 2023.
The IBM clock was from the original 1954 portion of the school, while the Simplex one was in the 1971 gymnasium/pool addition. (images censored to respect privacy)
I unfortunately don’t have any way to test them.
There’s many different types of clocks and clock systems that ibm/simplex sold. I think this is one of the 3 wire systems, which, would have had dedicated wiring for the clocks. There’s a good youtube video you can find about these.
Other simplex clocks used carrier current - they would plug into any wall outlet and receive pulses that were blasted over the power lines by these big signal generators, it was used for anything from clock sync, bells/chimes, and even fire horns. You can usually spot these by the fact they will have 2 large inductors on the back, and the oldest models even had a vacuum tube.
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I remember my elementary school had a ton of these. The master controller was in the office, and it had a ton of buttons on it. (None of which I know the function)